STklos

STklos is a Scheme implementation that succeeded STk. It is a bytecode compiler with an ad hoc virtual machine which aims to be fast as well as light.

STklos
Developer(s)	Erick Gallesio
Initial release	January 17, 2001; 24 years ago (2001-01-17)[1] (version 0.50, first public release)
Stable release	2.10[2] / October 10, 2024; 9 months ago (2024-10-10)[3]
Repository	github.com/egallesio/STklos
Operating system	Cross-platform
Standard(s)	R7RS (mostly)
Type	Programming language
License	GPL
Website	www.stklos.net

STklos is free software, released under the GNU General Public License.

In addition to implementing most of R⁵RS, and a large part of R⁷RS, STklos supports:

• an object system based on CLOS with multiple inheritance, generic functions, multimethods and a MOP
• a module system
• easy connection with the GTK toolkit
• a low-level macro system that compiles macro expanders into bytecode (syntax-rules is also present as a high-level macro system)
• a full Numerical tower implementation, as defined in R⁷RS
• Unicode support
• Perl compatible regular expressions via PCRE library
• a simple foreign function interface via libffi
• being compiled as a library and embedded in an application
• native threads, using the libpthread library. The API conforms to SRFI-18
• a number of SRFIs^[4]
• easy access to SLIB
• an HTTP client